1. Field of the Invention
The present invention relates to cable insulation strippers. More particularly, the automatic field cable stripper of the present invention is an attachment for al handheld power drill which is used for stripping external insulation from high voltage or high tension electrical cables in the field.
2. Description of the Related Art
Attachments for use with power drills to strip insulation from electrical cables are known. However, most such attachments cut the insulation using one or more knife blades that are adjustable and/or removable rather than being permanently fixed, i.e., being an integral part of the device.
U.S. Pat. No. 969,339, issued to Chytraus on Sep. 6, 1910, teaches a device for cutting insulation from conductors manually using a pair of knife blades positioned parallel and perpendicularly to the conductor, respectively, to perform the cutting, as shown by reference numbers 16 and 21 of FIG. 1 of the patent. U.S. Pat. No. 3,614,905, issued to Bieganski on Oct. 26, 1971, teaches a cable stripping apparatus having a pair of cutters used to apply an annular incision to the outer insulation that is then removed axially away from the remainder of the conductors to expose the underlying conductors. The apparatus is provided with a stop to limit the depth of the cut.
U.S. Pat. No. 3,623,384, issued to Murphy on Nov. 30, 1971, teaches a device for removing cable insulation using knives that can apply both a longitudinal cut, as well as a radial cut, using two different cutting blades, as shown by reference number 29 in FIG. 8 and reference number 70 in FIGS. 15 and 16 of the Murphy patent. U.S. Pat. No. 4,027,557, issued to Stepan on Jun. 7, 1977, teaches a wire stripping device that uses a single swinging knife blade, as shown by reference number 9 in the Figures.
U.S. Pat. No. 4,059,893, issued to Solury on Nov. 29, 1977, teaches a coaxial cable cutting tool. U.S. Pat. No. 4,317,279, issued to Smith et al. on Mar. 2, 1982, teaches a handheld power drill that drives a coaxial cable trimmer which uses a pair of circumferentially positioned blades to progressively xe2x80x9cshave offxe2x80x9d the outer insulation from the cable. The blades are individually removable from the multi-part device. Trimmed insulation shavings exit the tool through ports provided in the tool.
U.S. Pat. No. 4,594,029, issued to Michael III on Jun. 10, 1986, teaches a method of trimming a cable using a rotating hand tool. The multipart device includes a two-bladed cutter which trims away the insulation and outer conductor from coaxial cables. U.S. Pat. No. 4,729,268, issued to Morrow on Mar. 8, 1988, teaches a coaxial cable skiving tool. U.S. Pat. No. 4,914,818, issued to Hall et al. on Apr. 10, 1990, teaches a handheld manually operated coaxial cable cutter.
U.S. Pat. Nos. 5,077,895, issued to Okubo et al. on Jan. 7, 1992, and 5,487,220 issued to Saitou on Jan. 30, 1996, both teach an exfoliating device for removing cable insulation having cutting blades capable of cutting the insulation either longitudinally or radially. U.S. Pat. No. 5,105,542, issued to Nakajima et al. on Apr. 21, 1992, teaches a tool that cuts away the outer insulation from a coaxial cable in a spiral fashion.
U.S. Pat. No. 5,511,305, issued to Garner on Apr. 30, 1996, teaches a coaxial cable stripping device that removes the insulation in a spiral fashion, similar to the action of a pencil sharpener. U.S. Pat. No. 5,664,324, issued to Hoffa et al. on Sep. 9, 1997, teaches an apparatus for radially cutting and then stripping the insulation by removing it axially from the remaining conductor. U.S. Pat. No. 5,673,486, issued to Brown on Oct. 7, 1997, teaches a cable insulation stripper that cuts specific individual lengths of slugs of sleeves.
U.S. Pat. No. 5,829,141 issued to Pick on Nov. 3, 1998 teaches a device for cutting cable insulation which includes a repositionable knife that can be set to cut either circumferential or lengthwise cuts. U.S. Pat. No. 6,161,289, issued to Alexander on Dec. 19, 2000, teaches a wire stripper attachable to a power drill or a ratchet having openings to accommodate various sized conductors and that can strip insulation in a spiral fashion.
U.S. Pat. No. 6,381,850, issued to Warner on May 7, 2002, teaches a cable stripping device that can be rotated using a drill. U.S. Pat. No. 6,397,474, issued to Losinger on Jun. 4, 2002, teaches a cable preparation tool particularly for use on corrugated coaxial cables. UK Patent No. 1,057,254, published Feb. 1, 1967, teaches a cable sheathing stripper including a curved knife blade.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus an automatic field cable stripper solving the aforementioned problems is desired.
AIl The automatic field cable stripper is a three-part device attachable to a handheld power drill that is capable of stripping the outer insulation layer from an insulated conductor cable. The device includes an arbor, a cutter, and a shield which are threadably connected together. The arbor provides a support for attaching the device to the chuck of a power drill. During use, ribbon-like shavings of the removed cable insulation are produced as the knife edges of the cutter cut the insulation. The shavings exit the device through ports in the shield.
The cutter includes a plurality of annularly arranged knife edges that are an integral part of the cutter, i.e., the knife edges are not separable from the cutter. Also, the knife edges are oriented in a manner that removes the insulation along a direction that is coaxial with the cable. Moreover, the cutter includes an internal stop to limit the length of insulation removed from the cable.
The cutter and shield are sized to correspond to the size of a conductor cable and with the thickness of the insulation, i.e., the cutter and its shield are matched to a specific conductor cable. A set of differently sized cutters with housings are needed to remove insulation from correspondingly sized cables.
Accordingly, it is a principal object of the invention to provide a three-part cable stripper that is powered by a handheld power drill to remove the outer layer of insulation from a cable, including a cutter provided with a plurality of annularly placed knife edges that remove insulation axially along the length of the cable.
It is another object of the invention to provide a cable stripper attachment for a power drill having an internal stop for removing a predetermined length of insulation from a cable.
It is a further object of the invention to provide a set containing cable strippers for power drills having various sizes corresponding to various cable diameters.
It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.